Variability in the distribution of ozone over land and

marine regions in the Indian region

S. Lal1, S. Venkataramani1, S. Srivastava1, S. Gupta1 and M. Naja2

1 Physical Research Laboratory, Ahmedabad, India 2 Aryabhatta Research Institute of Observational Sciences, Nainital,

India

shyam@prl.res.in

Current focus of tropospheric research is on chemistry-climate interactions especially over the Asian region

Monthly mean surface ozone increase from 2000 to 2100 based on average results of 10 models. Prather et al., JGR 2003

Akimoto (2003) Science

NOx emissions during 1990-2020

(Gg NO2/yr), Streets et al. JGR 2003

1990 2000 2010 2020

China 8273 13719 21906 32364

India 3481 5615 10842 22824

Sheel et al., AE, 2010

DJF MAM

JJA SON

Average Seasonal Wind Streamlines

Winter

Surface ozone and related trace gases measurements at different sites in India

Time (IST)

Ahmedabad Mt. Abu

Nainital

Thumba

Port Blair

Tirupati

Ooty

New Delhi

Study of ozone and related trace gases at Ahmedabad

Surface ozone at Ahmedabad– Longterm Trends

Naja and Lal, GRL , 1996

Average ozone mixing ratio

increased from 14.7 ppbv

during 1954-55 to 25.3 ppbv

during 1991-93, resulting in

a linear increase of

~ 1.4%/year

1400 hrs

Time (IST)0 4 8 12 16 20 24

Aver

age

ozon

e (p

pbv)

0

20

40

60

1991 - 93

1954 - 55

1400 hrs

Month

0 1 2 3 4 5 6 7 8 9 10 11 12

Mon

thly

Ave

rage

ozo

ne (p

pbv)

0

20

40

60

1954 - 55

1991 - 93

Mt Abu Observatory in the early 1990’s

Diurnal variation of ozone at Mt. Abu (24.6N, 72.7E, 1680m amsl)

Mt Abu (1993-2000)

O

3 (

pp

bv

)

-4

-2

0

2

4

Time (LST)0 6 12 18 24

O

3 (

pp

bv

)

-4

-2

0

2

4

[a]

[b]

Winter (DJF)

Autumn (SON)

Mauna Loa

Spring (MAM)Summer (J_A)Mauna Loa

Autumn and Winter : Winds from north Spring and Summer : Winds from south-west and south

Naja et al., AE 2003

Regional and Local effects

Months

J F M A M J J A S O N D

Av

g O

zon

e (p

pb

v)

0

20

40

60

80

100

Day time avg (12-14 hrs) at Ahmedabad (1991-95)

Monthly avg at Mt Abu (1993-97)

Night time avg (01-03 hrs) at Ahmedabad (1991-95)Best fit line for day time avg (12-14 hrs) at Ahmedabad

~ 5-10 ppbv Local (Amd) Contribution

~ 12-15 ppbv Regional Contribution

Ozone at Mt. Abu (24.6N, 72.7E) and Nainital (29.4N,79.4E)

Kumar et al., JGR, 2010

Variations and levels of ozone and related trace gases are different over different parts of India suggesting diverse regional emission sources

Model derived contributions (in ppbv) for Nainital .

0

20

40

60

80

100

Av

era

ge O

zo

ne (

pp

bv

)

0

20

40

60

80

100

Nainital - 2007

Nainital - 2006

Nainital - 2008

Monhtly Average (Mt Abu)

Hourly Average (NTL - 2007)

Hourly Average (NTL - 2006)

Hourly Average (NTL - 2008)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

5

10

15

20Startospheric Ozone

European Emissions

South Asia Emissions

Maximum ozone : Mt. Abu - Autumn/Winter Nainital - Spring/Summer

The slope (∆CO/∆NOx) is related to primary emission sources of

these species. In high temperature combustion processes (e.g., use

of fossil fuel in vehicles and power plants) these slope values are

lower than those emitted from biofuel and biomass burning

These results indicate that emission from biofuel combustion and

biomass burning play major role in the observed distributions of

various trace gases in India.

CO-NOx Relation

AHMEDABAD

HISAR

KANPUR

CHINA US

EUROPE

CO

/NO

x

0

10

20

30

40

Japan

ECC Ozone sonde (GPS)

25 m

Balloon

Radio sonde

Parachute

Vertical distribution of ozone over Ahmedabad (June 2003- July 2007)

Total ~ 80 balloon flights Effects of :

Regional Pollution -

Spring and summer

seasons

Longrange Transport –

Spring season in the free

troposphere

Marine -

Monsoon season in the BL

Longitude (oE)

55 60 65 70 75 80 85 90 95

La

titu

de

(oN

)

0

5

10

15

20

25

30

19 M

20 M

24 M

26 M28 M

22 M

30 M1 A2 A

4 A

6 A

8 A10 A

12 A19 A21 A

23 A 25 A

27 A

28 A

29 A

30 A

3 My

4 My 5 May

7 My

9 My

Trivandrum

Goa

Chennai

Bhubneswer

Kochi

INDIA

Bay of Bengal

Arabian Sea

Study of ozone and meteorological parameters over Bay of Bengal (BoB) and Arabian Sea (AS)

Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB)

Bay of Bengal (18 March to 13 April,06)

Arabian Sea (18 April to 11 May,06)

29 Ozone and radio sondes

Intrusion of land plume over North Bay of Bengal (N-BoB) and North Arabian Sea (N-AS)- ICARB 2006

Transport of ozone rich layer (60-90 ppbv)

over N-BoB attributed to advection of air

from Indo-Gangetic Plain.

Potential Source Contribution

Function (PSCF) analysis

NAS – SAS

N-BoB S-BoB

N-AS S-AS

NBoB - SBoB

Srivastava et al., JGR (in press)

Nainital

Kanpur Agra

Shillong

Kolkata

Nagpur Bhubneshwar

Vishakhapatnam

Hyderabad

Gadanki

Thumba

Ahmedabad

Mt. Abu

Port Blair

Thalassery Ooty

Anantpur

Kullu

Mt Abu Observatory in the early 1990’s

Measurements of ozone and related trace gases in different

regions : A network of environmental observatories in India under ISRO GBP

Mt. Abu

24.6N,72.6E

~1.7 km

Nainital

29.4N,79.4E

~2.0 km

Ooty

11.4N,76.7E

~ 2.5 km

Summary :

• Tropical Asian region - a natural photochemical laboratory.

• Chemical changes are occurring due to rapid industrialization and economic growth.

• Emission characteristics and transport pathways differ from region to region and from season to season.

• Surrounding marine regions affected by transport for the continental polluted air.

• There is a need for understanding types of emission sources, their budgets and chemical and transport processes for predicting future changes in this region.

Thanks for your attention